1995 Nissan Altima Stalling - Need help to diagnose

Hello All

My 1995 Nissan Altima, might I add up this this point was in perfect running condition. A month ago the car started stalling first when at a stop, now the idle is very rough and the engine cuts off when accelerating from a stop. This always happens when I first strat and drive the car for the day, thereafter the problem is not so obvious.

My mechanic had a look at the car and suggested spraying carb cleaner into the throttle body, this helped for about a month. I sprayed the carb cleaner and then the car was running smoothly for 5 days. Then the problem will come back, at a stop the car will start to idle rough then switch off, then sometimes it will idle ok, but when I start to accelerate it will cut off. So I started using fuel cleaner and replaced the plugs and checked spark plug wires and distributor cap. No problems with any of these. Checked the hoses no problems. Eventually took this car into the Nissan dealer to have it diagnosed.

They suggest that the spark plug wires, plugs and the valve cover be changed. Also that the 4 motor mounts be changed(non-related)...

I am trying to understand why the carb cleaner works and if the dealer suggestion is valid or if there could be a deeper problem.

Any help will be appreciated.

Linus

Reply to
LinusV
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I would guess that the problem is a fuel metering problem caused. The engine is getting all the air it needs when you push the accelerator, but the computer is not matching the air with fuel and then the engine dies. The computer uses about 14 sensors to measure the fuel delivery requirements, but for air measurement there are only 2 or 3. The least like is the Air Temperature Sensor. The other two are the Mass Airflow sensor (MAF), and the Manifold Absolute Pressure sensor (MAP). The carb cleaner acts like fuel, but it's potentially cleaning the MAF sensor. Also, although unlikely, the Air Filter or it's passage could be blocked.

The idea that spark plugs (and the spark altogether) could be the problem is not entirely out of the question. If there is more trouble with accelerating on a very humid or "moist" day then the spark plug wires are probably arcing off. (Moisture causes this in older wires).

Hope that helps.

Reply to
MegAltima

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